How can I reproduce the same mesh many times 9000 (seriously)
Every time yo find yourself doing the same action over and over, think that there has to be a better way, either by instancing, using arrays or scripts to save you from tedious tasks.

In this case creating a large number of copies of the same object can be done with the Array Modifier

Create your base object.

Add an Array Modifier.

That will duplicate the object however many times you want it. The default is on the X axis (but you can modify that).

Then add a second array to duplicate however many times you need in the Y axis (or any other axis you need)